What causes white spots on teeth? Dentists explain, plus how to fix them

You snap a selfie, zoom in and there it is! A milky little smudge on your front tooth where everyone can see it. Is it a stain, a cavity or nothing at all?

White spots on teeth are usually a change in the enamel itself, not something sitting on top. And they’re common, especially after braces. More than half of people with braces develop them. Some spots are just part of your smile, harmless and here to stay. Others are early warning signs of a cavity, but you may have a window to stop them and potentially reverse the damage.

How do you tell them apart? We asked three dentists what causes white spots, how to get rid of them and when it’s time to book an appointment. 

What causes white spots on teeth?

White spots are really a trick of the light. “Healthy well-formed enamel is translucent,” notes Alice Hoang, DMD, a dentist at Brooklyn Mint Dental. When enamel becomes porous, light scatters off it, and the area looks white. There are several reasons why this might happen.

Mineral loss from plaque

Plaque is a sticky film of bacteria that feeds on sugar and makes acid that “eats away at the enamel, making it chalky,” Hoang says, and those weak spots “can eventually acquire stains.” Braces make it worse. “Plaque gets left around the brackets,” explains Nayson Niaraki, DMD, an orthodontist at Smilebar, and those are some of the hardest spots to clean. Months of acid exposure there can leave chalky outlines that only show up once the brackets are gone. 

Fluorosis

Fluoride is a mineral added to toothpaste and many water supplies. It “creates a shield making enamel more resistant to acids,” Hoang says. But too much of this added fluoride while teeth are still forming can backfire. 

“Fluorosis occurs when a child gets too much fluoride during the development of the permanent teeth,” says Liel Grinbaum, DMD, a pediatric dentist at Smiles + Grins. He explains that it shows up as “horizontal or vertical white lines or cloudy-like spots.” It can happen when young children swallow too much fluoride toothpaste over time.

If you’ve had these spots since childhood, you can probably relax. “Most cases are non-harmful and are just a cosmetic concern,” Grinbaum says. 

Enamel that formed too thin or too soft

Sometimes enamel doesn’t form properly while teeth are developing in childhood. That can happen in two ways. With enamel hypoplasia, “a tooth develops with less enamel than normal,” Grinbaum says, so the enamel ends up too thin. 

With molar-incisor hypomineralization, or MIH, there’s enough enamel, but it never fully hardens. It usually appears on the back molars and front teeth, and it affects about 15% of kids and teens worldwide. The spots can look white, yellow or brown. 

With either condition, the weaker enamel means these teeth can be “hypersensitive at times and more prone to cavities,” Grinbaum says. 

Dehydration

Some white spots are just a sign of thirsty teeth. If you sleep with your mouth open or have just used whitening strips, your enamel can dry out. That changes how it reflects light, making patches look whiter, according to Hoang. Give it time, and the spots fade as your teeth rehydrate.

Is it harmless or early decay?

Location and timing are your best clues to whether a spot is harmless or not. Early decay, or caries, “usually appears as chalky white spots near where plaque accumulates, like the gum line,” Grinbaum says. “Fluorosis tends to look more like faint white streaks randomly on the teeth, while MIH can appear as well-defined white, yellow or brown patches.” 

If you’ve had a spot for as long as you can remember, it’s likely developmental. “It doesn’t change over time like early decay can, and often does,” Hoang points out. A spot that’s new or growing is the one to get checked. 

How to fix white spots on teeth

Stopping the damage isn’t the same as erasing marks. “No at-home remedy will effectively get rid of white spots,” Hoang stresses. Fully removing a spot usually takes a trip to the dentist. However, DIY care can keep spots from “worsening and becoming true decay,” she says, and it may soften them over time. Here are your options. 

1. Remineralizing toothpaste

“For mild spots, I’d start with fluoride toothpaste, sometimes with a fluoride varnish in the office,” Niaraki recommends. Be patient, though. “Improvement can take months, and the white color may not go away completely.”

Limited research supports this approach. When scientists pooled studies of people with white spots after braces, fluoride and calcium-phosphate products both helped restore some lost minerals, but only modestly. 

If your dentist thinks you need more firepower, they may prescribe a high-fluoride toothpaste. But if you prefer something over-the-counter, hydroxyapatite toothpaste can help remineralize areas already affected by acid, Hoang says. Just know “it’s not as effective at prevention as fluoride,” she adds.

One catch is that these products help spots caused by mineral loss, not the ones you were born with. Fluoride “won’t affect developmental white spots, such as MIH,” Grinbaum cautions.

A basic tube of fluoride toothpaste costs a few dollars, while hydroxyapatite typically costs more. Grinbaum says products containing calcium and phosphate to help strengthen weakened enamel, like MI Paste, are typically available at a dentist’s office for roughly $20 to $40 per tube. Just keep in mind they often contain casein, a milk protein, so they’re not appropriate for people with a milk allergy.

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At $9 for two tubes, this is Niaraki’s pick for a no-frills fluoride toothpaste. 

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Niaraki calls this one “interesting because it combines hydroxyapatite with fluoride.”

2. Better plaque control

Good brushing won’t make a spot disappear, but it might stop new ones from forming and keep existing ones from turning into cavities. If you wear braces, Niaraki recommends brushing three times a day with fluoride toothpaste. “Pay attention to where you’re brushing. Above and below the brackets are easy places to miss.” A small interdental brush helps get under the wires, he says, along with daily flossing and less sipping on sugary drinks.

Even if you don’t have braces, plaque still builds up along the gum line, right where early decay spots tend to develop. Brushing twice a day with fluoride toothpaste and flossing daily keeps it in check. An electric toothbrush can make the job easier, with prices running from around $30 to $200. 

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Niaraki likes these tiny interdental brushes for cleaning around brackets and under wires. That’s exactly where white marks tend to form. 

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If you’re ready to retire your manual toothbrush, this $60 electric version comes with six brush heads to last you more than a year.

3. Whitening, with a caveat

Whitening brightens the whole tooth, so it can help faint spots blend in a little as the enamel around them gets lighter. But it can’t fix the spot itself, and it can make it stand out more at first, partly because it temporarily dries out enamel. Hoang compares it to pushing up every slider on a sound system at once. Everything gets brighter, but the spot and the rest of the tooth eventually hit the same ceiling. 

If your braces just came off, don’t rush it, especially if you have white spots. “Have them checked first. I’d usually give it a few months,” Niaraki says. Whitening also “won’t repair the enamel, and it can cause sensitivity,” he warns. 

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When you’re ready, you may want to start with at-home strips rather than a more expensive in-office treatment. They’re used for roughly 30 minutes daily for about three weeks, depending on the kit. For gentler everyday options, see our best whitening toothpaste roundup. 

4. Resin infiltration

“For spots that stay noticeable, a treatment called Icon resin infiltration can help,” Niaraki suggests. “It fills the tiny pores in the enamel so the spot blends in better. You can often see a difference that day, although it doesn’t work equally well on every spot.” 

It works best on shallow spots, about half a millimeter deep or less, according to Hoang. In a review of clinical trials, resin infiltration masked white spots better than fluoride varnish or no treatment, though the researchers noted that only a few high-quality trials exist and the effect was moderate.

If you decide to try it, the treatment usually takes just a single visit, and costs a few hundred dollars per tooth. Insurance may not cover it, so check before you book. 

5. Bonding or veneers

For deeper or stubborn spots, your dentist can cover them with tooth-colored resin, called bonding. Hoang uses it for spots up to about 2 millimeters deep. Veneers are a bigger step, saved for severe or tricky cases.

If a dentist jumps straight to veneers, think twice. “If you like the shape and size of your teeth and a dentist recommends veneers, I would strongly suggest seeking a dentist well-versed in non/minimally invasive dentistry for a second opinion,” Hoang advises.

What does treatment cost? “Fees vary by location down to the zip code,” Hoang says. To get a ballpark for your area, she suggests the free cost lookup at FAIR Health Consumer, which shows typical prices with and without insurance.

When to see a dentist

Sometimes, it’s best to see a professional. “Any new spot should be checked,” Niaraki urges. “Definitely don’t wait if it’s getting bigger, developing a hole or causing sensitivity or pain.” And no pain doesn’t mean no problem. “Early decay often doesn’t hurt, so lack of pain doesn’t tell you much,” he adds.

Kids’ teeth follow the same rule. If a spot’s been there from day one, it’s probably developmental. If it’s new, it could be the first sign of a cavity, according to Grinbaum, so it’s worth a dental visit sooner rather than later. 

Most white spots can be treated, but timing is everything. “Catching enamel changes early gives us the opportunity to remineralize and protect the teeth, often avoiding more extensive dental treatment later on,” emphasizes Grinbaum. So the next time you notice a white spot, don’t panic. Just book the appointment.

Meet our experts

• Alice Hoang, DMD, dentist at Brooklyn Mint Dental, Brooklyn.

• Nayson Niaraki, DMD, orthodontist, co-founder and clinical director at Smilebar, Boston.

• Liel Grinbaum, DMD, pediatric dentist and founder of Smiles + Grins, New York.

Our health content is for informational purposes only and is not intended as professional medical advice. Consult a medical professional on questions about your health.